Pictures would help but it sounds like he's after more work. If your not happy with the tilers work call him back Alternatively you can buy grout pens, they're expensive seeing as they look no different than an ordinary pen but they do the job.

You might be pleasantly surprised how different it will look when you change the wall colour. Perhaps if you didn't that first, you'd not need to change the grout. I'd agree; if the tiles aren't symmetrical then a darker grout line would highlight this. I'd also agree that dark grey would look great - you have this in your floor mats and it looks nice against your gorgeous floor tiles. We went grey in our ensuite. Hubby was concerned it would be dark, but we love it. Worst case - if you change your mind, paint is an easy swap. Good luck ;)

Hi, I would suggest a pale grey grout as it is subtle and much more forgiving than white. I have attached a couple of examples where I have used a mix of dark and light tiles with a light grey grout. Hope this helps, David.

I used white 40x15cm tiles in my shower, fixed brick-bond, landscape, and almost black grout. The tiler said it took him longer than usual to make sure it looks neat and it's pristine. Agree with all comments about flooring - I inherited cream floor tiles with cream grout on my ground floor. Horrendous - just don't look too closely :-) x